2010,BMW 318i, car is shaking. Why?

Hi when I start my BMW 3 series 318i 2010 (automatic) the car shakes and the revs go up whilst in park mode. I get out of the car and the exhaust pipe is shaking. When I drive the car it stays stuck on the first gear for while until you hear a bang noise and the gear changes some times I have let go of the gas for it to go to the next gear. When I put the heating on or the AC the car sometimes starts to shake and the acceleration goes heavy too.
My car has an automatic transmission.